Ok. What that page I linked to explains, is that to have multiple Human Activities, the best pattern to do this is create a seperate Process for that activity, which launches on the creation of a record in an Entity. But it is important to understand, that each Human Activity should be accompanied by unique data for that Activity (which makes sense, you wouldn't want mulitple humans overwriting their input or whatever they're supposed to do), and the creation of that data can trigger a new (sub)Process to start.